Preparation and characterization of hydroxyapatite incorporated silica aerogel and its effect on normal human dermal fibroblast cells

The development of biomedical materials is increasing nowadays due to the increasing demands in medical area and various manmade advanced materials have been explored. In this study, the hydroxyapatite (HA) which is widely used biomaterial has been incorporated in silica aerogel (SA) through sol-gel ambient pressure drying (APD) technique using amorphous silica from rice husk ash. The HA incorporated SA (HAESA) samples with different weight ratio of HA/SiO 2 (0.05, 0.1, 0.5, 1.0 and 1.3) were characterized and studied for their in vitro biocompatibility against normal human fibroblast cells. Based on the characterization results from Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, energy dispersive X-ray analysis, transmission electron microscope and thermogravimetric analysis, the HAESA samples with lower weight ratio of HA/SiO 2 (0.05, 0.1 and 0.5) were silica-rich materials compared to that of higher weight ratio (1.0 and 1.3) which were silica-deficient materials. This resulted in different effects towards in vitro cell viability where the silica-rich HAESA samples have higher biocompatibility compared to that of silica-deficient materials based on trypan blue and cell viability assays. The optimum weight ratio of HA/SiO 2 was for HAESA-0.5 (weight ratio of 0.5) in which it has the characteristics of HA and SA, and this eventually resulted in the highest cell viability which is up to 180% after 48 h exposure. Therefore, it can be concluded that the right amount of HA incorporated in the SA network can be performed by using sol-gel APD technique and resulted in high biocompatibility which is suitable to be used as alternative biomaterial for soft tissue application. A series of hydroxyapatite (HA) incorporated silica aerogel with different weight ratio of HA/SiO 2 was prepared via sol-gel ambient pressure drying (APD) technique, characterized and analyzed for their cell viability against normal human fibroblast cells. The weight ratio of 0.5 (HA/SiO 2 ) was the optimum ratio where it has characteristics of silica aerogel and hydroxyapatite and resulted in the highest cell viability. Highlights Hydroxyapatite incorporated silica aerogel (HAESA) was synthesized via sol-gel APD technique. Silica-rich HAESA have higher cytocompatibility against human fibroblast cells. HAESA with weight ratio of hydroxyapatite/SiO 2 equal to 0.5 has the highest cytocompatibility.